In artificial intelligence, an expert system is a computer system that emulates the decision-making ability of a human expert.
Expert systems are designed to solve complex problems by reasoning about knowledge, like an expert, and not by following the procedure of a developer as is the case in conventional programming.
The first expert systems were created in the 1970s and then proliferated in the 1980s. Expert systems were among the first truly successful forms of AI software.
An expert system has a unique structure, different from traditional computer programming. It is divided into two parts, one fixed, independent of the expert system: the inference engine, and one variable: the knowledge base. To run an expert system, the engine reasons about the knowledge base like a human. In the 80s a third part appeared: a dialog interface to communicate with users. This ability to conduct a conversation with users was later called "conversational".
Why this is part of Dragonfly Algorithm?
Because 'Dragonfly' (defensive version) will use 'Expert System' to help user defend against hacker attack. More accurately, it'll be conversational system that supports decision making (version which is partly automated). It should be simple to use, but allow for detailed decision making if neccessary.